Ball recovery system

ABSTRACT

A tennis ball recovery system utilizes an elastic screen (15) suspended from a back stop at an angle and is joined to a trough that lies on the ground by means that allow the screen (15) to pivot as the trough is moved to a storage position against the back court fence (12). In the operative position the screen is at an angle with respect to the vertical. The trough has a frontal wall (18) that rises at a small angle to the ground and this wall terminates in a lip (22) that lies over the bottom wall (17) of the trough. A feed screw (31,31&#39;) fits in the bottom of the trough to feed balls retrieved to a central point where they are discharged into a bucket (42).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to PCT application No. PCT/US90/05305 whichis a continuation-in-part of my application Ser. No. 07/451,642, filedDec. 18, 1989 (abandoned) which in turn was a continuation-in-part ofapplication Ser. No. 07/307,782 filed Jan. 30, 1989 (U.S. Pat. No.4,575,081).

BACKGROUND OF THE INVENTION

The present invention relates to a ball returning system for tennis orgolf comprising a ball collection assembly which in turn comprises ascreen suspended from a vertical structure and a trough connected to thebottom of the screen in which the balls are received. Balls are returnedvia a conduit connected to the trough, to a ball propulsion device fromwhence balls are delivered to a player.

In U.S. Pat. No. 4,575,081, there is disclosed a means of retrievingtennis balls which was useful, particularly during instructionalsessions or other practice sessions, either with or without a partner.The prior system utilizes a wire fence as the damping screen which wouldbe loosely hung off of a standard back court fence so as to interceptthe balls which then would drop onto a resilient apron and thence rollinto a collection trough. The major difficulty that has been experiencedwith this and similar constructions that have vertically orienteddamping screens, lies in the fact that the screens either hang looselyor are stretched in a vertical attitude above the trough and it is thisscreen orientation that causes the balls to sometimes bounce back ontothe court. Generally these devices have aprons or wide troughs and, onoccasion, the apron does not always operate to restrict the ball'saction sufficiently so that all of the balls will land into the trough.Also many of the balls do not hit the damping screen in a uniformpattern and on occasion will drop directly down into the trough whichdoes not sufficiently damp the ball, the balls bouncing out of the apronand onto the court.

Another suggestion in the prior art that utilizes a loose net as adamper for tennis balls that are driven towards it so that the samecould fall into some sort of a trough, is seen, for example in theHodges patent, U.S. Pat. No. 4,025,071. Balls, however, striking a loosenet that is not fastened at the bottom edge, tend to deflect the net toa considerable degree and may not always permit the ball to fall into acollection trough thereunder so that at times, even devices of thisnature do not operate with total ball recovery. This result isrecognized in the Hartland patent, U.S. Pat. No. 4,456,252, whichutilizes a sweep rack to insure that the ball falls into the collectiontrough after they have been stopped by the net.

There have also been some suggestions in the prior art of movingcaptured balls in troughs by the use of conveyers as, for example, inthe Salansky patent, U.S. Pat. No. 4,621,812, where a tennis ball ridessolely upon a helical conveyer, the difficulty with this type ofconstruction lies in the fact that the tennis ball can readily bedislodged from the conveyer. A similar arrangement of a conveyer is seenin a second Salansky published application (PCT WO85/04336-EPO 177,514of Apr. 3, 1985), where a net is held in tension along its upper andlower edges by a spring loaded frame and the net is attached at thelower edge to a support which in turn supports a ramp with a trough thatcontains a helical screw means for moving the balls.

SUMMARY OF THE INVENTION

The present invention discloses apparatus that recovers tennis or golfshots which have widely differing momentums (i.e. speed and directions)by instrumentalities that change the momentum of the tennis or golfballs so that the balls have a consistently predictable direction ofmovement, which enables consistent (up to about 99% or more) recovery.

Specifically in one aspect of the invention, the apparatus includes acontainment screen suspended from a vertical back court structure (e.g.fence) at an angle so that an apron is not required and also includes atrough defining a generally horizontal ball return channel having abottom surface. The screen and its inclination angle provide a uniquefunction the ball maintaining contact with the screen so that the balltracks on its original vertical trajectory and its return to the trough.The trough has means for attaching the screen to the rear of thechannel, which allows the screen to pivot as the trough is moved fromits storage position in which the trough contacts the vertical backcourt structure to its operative position in which the trough is forwardof the vertical back court structure. Thus, in the operative position,the screen is at an angle with respect to vertical, so that the top ofthe screen is further from the playing area than the bottom of thescreen. A ball striking the screen is held in contact with the screenfrom the moment of impact through its ascent upwards and even during themoment that either gravity or the projecting stop causes the ball totravel smoothly downwardly along the screen, in a relatively repeatabletrajectory, to the trough. A stop surface on the trough is positionedabove the bottom surface or floor of the ball return channel and it ispositioned forward of the means for attaching the damping screen adistance less than the full diameter of a tennis ball. This geometryoperates on balls presented from the screen so that the ballssimultaneously encounter the floor and stop surface. This geometry doesnot permit the balls to be deflected upwardly (over the stop) by thebottom surface of the ball return trough. Thus, according to theinvention, balls thus presented from the screen are reliably trapped inthe trough.

In preferred embodiments of this aspect of the invention, the stopsurface is the free rear edge of an inclined front wall of the trough.The front of the trough thus presents a very slight incline, allowingrecovery of rolling balls presented from the court that would nototherwise be accepted into the trough. Even slowly rolling balls cantravel over the wall which is inclined at an angle of between 5° and 50°(most preferably 10°-40°). Moreover, the inclined wall is short(preferably less than six inches in length) so that it permits easystorage and does not present a hazard to players on the court.

Additional space economy is provided by the use of a flexible screwconveyor which rests on the front of the bottom wall surface of thechannel, below the inclined front wall. A vertical wall runs between theinclined wall and the bottom wall, to support the free edge of theinclined wall, and the flexible conveyor is positioned at the junctureof the bottom wall and the vertical wall. When rotated in the properdirection (i.e., if the screw is a right-handed helix, it is rotatedcounterclockwise), the conveyor screw cams against the two walls so thatit is held in a position that will not interfere with balls entering thechannel. Most preferably the flexible conveyor screw is supported onlyat the motor end, so that it is easy to install and disassemble.

In preferred embodiments, the containment screen comprises elasticnetting having a lower edge of sheet material that is fixed to thebottom wall of the trough. The front wall of the trough is inclinedtoward the screen and has a stop surface that terminates at a height atleast one-third the diameter of a tennis ball. The damping screenincludes an upper marginal edge binding with a loose layer overlying thescreen so that balls moving up the screen are prevented from climbingover the top edge of the screen. Also preferably, the bottom wall of thetrough is provided with a groove and the screen is affixed to the troughby a cooperative fastener that fits into the groove; for example, thescreen includes an extended cylindrical elongated strip formed by a ropesewn within the sheet material which engages the groove.

In another aspect, the invention generally features tennis ball recoveryapparatus having a polyester coated fibre screen that is suspended byshock cords for additional resilience and then extends downwardly at asmall angle off the vertical and which has affixed to the lower edgethereof a sheet material that is somewhat flexible but yet exhibits acertain stiffness as for example, a vinyl, or heavy fabric. Thisterminal portion is then affixed to a wall of the trough which has onewall with a capture lip thereon. Within the trough a helical feed screwis fitted to feed the balls to a central location. The essential actionof the flexible elastic screen is to dampen and contain the ball incontact with the screen as it strikes and throughout the ball's descentto the trough. Further, the angle of the screen combined with thetopspin on the ball, allows the ball to creep up the screen and then,after the ball has lost its momentum, it falls by gravity, continuallytracking the screen, down into the trough to be stopped by a lip on theremote wall of the trough from the screen.

The screen is fitted with an integral projection at its top and sideedges so that as some of the balls creep up the screen, should they havesufficient momentum to reach the top or the side due to particular spinaction or trajectory, they will be stopped because they will be trappedby the projecting stop and completely lose their momentum rather thangoing off the net completely.

In order that the invention may be more readily understood and furtherfeatures thereof appreciated, embodiments of apparatus constructed inaccordance with the invention will now be described, by way of example,with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of a portion of a tennis court showing theplacement of the invention relative thereto;

FIG. 2 is a side elevational view illustrating the screen and the troughin position and pulled out from the backstop;

FIG. 3 is an enlarged view showing the trough with the ball retainedtherein in phantom;

FIG. 3A is a view of a modified cross section of trough;

FIG. 4 is a view of a corner of the screen illustrating the projectingstops and the securement of the screen;

FIG. 4A is a view of the bottom corner of the screen; and

FIG. 5 is a fragmental view of the helix drive cable.

The tennis court has a flat rectangular surface 10 and in the case of afull court, will have a net stretched midway thereof. In theillustrative case, fencing about the court is illustrated, there being aback fence 12 supported on the plurality of posts 14. The back fence ofa tennis court is commonly made from a wire known as chain link andconveniently, in combination with the post 14, provides a mounting pointfor the damping screen of the instant invention.

The containment screen 15 of the instant invention may be constructed ofany suitable commercially available screening. For example, the screen15 may be formed of twine which is virtually identical to the net whichone might use for fishing or as the conventional tennis net at thecenter of the court. To this end, there are a plurality of rectangularopenings which are smaller than the tennis ball and this netting, whichexhibits some elasticity, will be preferably hung either from the chainlink back fence 12 or from a plurality of posts 14 by a number of shockcords 16 that have hooks 16a at either end thereof for convenience.Other forms of screening that are satisfactory are a polyester fibrecoated with a vinyl and formed into screening that may be as small as 3mm squares. As seen in FIG. 2 of the drawings, the screen 15 hangs downin a steep angle and is retained in that position by a plurality ofshock cords with hooks as seen at 16'. At the bottom edge of the net orscreen, there is affixed a stiff but somewhat flexible material 20 suchas a canvas that has a rope sewn within 21, the edge thereof forming anattachment hem for the net or screen 15.

Referring to FIGS. 2, 4 and 4A it will be noted that a projecting stop24 is provided at the top edge of the screen 15 and to add rigidity tothe stop that is in the form of an edge binding or flap, a rod 25 isinserted into the edge thereof. Similarly vertical edge stops 26 areprovided also having rods 27 in the terminal edges thereof. Desirablythe stops are portions of the screen that have been folded over a hem orterminal portion and are conveniently manufactured in this state.Alternately, the vertical edge stops may be rigid plastic that has beenformed into a U-shape and suitably attached to the edge of the screen.As seen in FIG. 4, the top edge of the screen has an upper fastener bar28 that provides an excellent attachment point of the hooks of the shockcord 16.

Referring to FIG. 3, the trough has a bottom wall surface formed from abase plate 17 and an angular or inclined front wall 18 that is held inposition by a vertical portion 18'. Spaced from the front wallsubstantially the diameter of a tennis ball, is a C shaped clip 19 towhich the fabric portion 20 with rope 21a sewn within hem 21 forming acylindrical edge that engages clip 19. The upper edge 22 of the frontwall 18 forms a front stop surface and is located substantially at orabove the diameter of a regulation tennis ball which insures retentionof the ball in the trough.

The trough of FIG. 3 has a dimension between the edge 22 and the clip 19just slightly less than the nominal diameter of a tennis ball. Inaddition, the tennis ball is retained in the trough by virtue of thefact that the rotation of the helical drive, the detailed description ofwhich appears below, is such that the tennis ball is nominally forcedagainst the clip 19 and to this end, as will be noted, there are twodrives towards the center, each driven by a separate motor so as toachieve the desired result.

The trough of FIG. 3A illustrates the retention of a tennis ball withthe stop surface edge 22' located below the diameter of the ball, orgreat circle thereof stated in geometrical terms. This arrangement ismade possible by the fact that the helical screw mechanism 31 forces theball toward the clip 19.

A helical drive mechanism 31, 31' is located within the trough andconsists essentially of a pair of central cables 32, 32' which havewound around the periphery thereof a cord 33 for example. As seen inFIG. 1, these cables may be conveniently driven by some form of a motors36, 36' which have output shafts connected to the cables 32, 32'. Inthis fashion, as a ball drops into the trough, the cable, which islocated in the V of the trough will be driven towards a portion thereof,for example centrally, from whence the balls may be then directed via aconduit 40 into a catch basket of a ball serving machine 42 as seen inFIG. 1, by the utilization of an air blower 44. The conduit 40 forconvenience may be made telescopic. Essentially therefore, the airblower acts as a pressurizing means that drives the balls through thetube and the tube can therefore be considered pneumatically operated.Normally, the trough has sufficient mass to be retained in positionahead of the back court fence of a tennis court. To insure the positiona pair of bars 48 are provided. The trough is readily moveablerearwardly to the backstop and for this purpose a rod 50 with a handleis supplied. In this fashion, a normal tennis game may proceed withoutany further modifications, something that is not possible with thedevices that are known in the prior art. There is, therefore, a ratherdecided advantage to this particular arrangement since mere removal ofthe ball throwing machine and the conduit together with moving thescreen or net structure rearward are all that are necessary.

One of the particular features of the invention is the design of thetrough. In the FIG. 3 configuration the trough has a substantialhorizontal portion that serves as an anchor for the netting while thefront wall 18 has a slope that permits balls that may be rolling on theground to roll up the incline and into the trough. Also the front wallextends beyond the vertical portion 18' thereof so that a lip is formedsubstantially at or just above the center of a normal tennis ball tokeep the ball in the trough. The balls are also kept in the trough bythe fact that the fabric portion 20 is clipped in at 19 and contacts theperiphery of the ball as a flexible web urging the ball against the lip,see FIG. 3.

The troughs are conveniently made in sections to facilitate storage andshipment. As seen in FIG. 2, the provision of the C shape clip allowssliding of the trough from the attachment hem 21. For movement, thetelescopic tube 40 is collapsed and the ball serving machine 42 isremoved. Then by providing a simple rod 50 with a handle that engagesthe trough as seen in FIG. 3, it may be moved against the backstop ofthe court to give full usage of the back court.

In operation, a ball striking the screen moves upward staying in contactwith the screen through the moment that either gravity or the projectingstop overcomes its upward movement. Since the screen is angled outward,the ball will travel smoothly downward along the screen to the trough.Upon striking the trough bottom wall 17, the ball will alsosimultaneously strike the stop lip 22 and be retained by the screenfabric portion 20 that is elastic. The geometry is such that the ballsare not deflected upward over the stop lip by striking the trough bottomwall or floor.

I claim:
 1. A ball practice system for use on a sport playing surfacehaving vertical support structure, said recovery system comprising:a. ascreen having top, bottom and side edges; b. means attaching the top ofsaid screen to said vertical structure to thereby suspend said screentherefrom; and c. a trough defining a generally horizontally ball returnchannel having a rear wall, a bottom wall surface having a rear edge anda front wall member having a free top edge, said rear wall being definedby said screen, said bottom wall having attachment means for attachingsaid screen thereto, said front wall member having a stop surfacepositioned above said bottom surface, said stop surface being positionedforward of said attachment means a predetermined distance, saidpredetermined distance being such that a ball rolling from the screenand into said through simultaneously strikes said stop surface and thebottom well, said attachment means allowing said screen to pivot whensaid trough is moved from a storage position in which it contacts saidvertical support structure, to an operative position forward of saidvertical structure so that said screen is at an angle with respect tovertical, the top of said screen being further from the playing areathan the bottom of said screen; whereby the momentum of a ball strikingsaid screen and the inclination of said screen will cause said ball tobe held in contact with the screen at the moment of impact and haveupward movement until gravity causes the ball to roll down the screenand into said return channel.
 2. The system of claim 1 in which saidfront wall member is inclined toward said screen the top edge of whichis free and comprises said stop surface.
 3. The system of claim 2 inwhich said trough has a vertical wall between said front wall means andsaid bottom wall to support the free top edge of said front wall member.4. The system of claim 3 in which said trough is fitted with a flexiblescrew conveyor and said conveyor is located at the juncture of thebottom and vertical walls and is rotated in a direction to cam theconveyor against said walls.
 5. The system of claim 4 in which saidflexible screw conveyor is supported only at the end of the trough. 6.The system of claim 1 in which said screen comprises elastic netting. 7.The system of claim 6 in which said attachment means includes sheetmaterial connecting said elastic netting to said trough.
 8. The systemof claim 1 further comprising means to manually move the trough betweensaid storage position and said operative position.
 9. The system ofclaim 8 further comprising a tube connected between said trough and aball serving machine, and air pressurizing means to drive balls fromsaid trough through said tube and to said ball serving machine.
 10. Thesystem of claim 9 in which said tube is connected to a central locationof said trough.
 11. In a tennis recovery system for a tennis playingcourt surface having a vertical back court support structure extendingabove said court surface, an inclined elastic netting screen having atop horizontal edge attached to said support above said court surfaceand a bottom edge positioned at said court surface, means defining abottom wall supported on said court surface, said bottom wall havingfront and rear edges, said screen bottom edge being attached adjacentsaid rear edge of said bottom wall, a front wall, said front wall beinginclined towards said screen and having a free top edge and a lower edgeattached to said front edge of said bottom wall, said screen, bottomwall and front wall defining a trough, said trough being spaced fromsaid support means to thereby place said screen in an inclinedorientation relative to said court surface such that a ball impactingsaid screen will roll down said screen and into said trough, said troughhaving a conduit attached thereto for conveying balls from said troughto a remote ball receptacle.
 12. The system of claim 2 or claim 11 inwhich said front inclined wall is inclined at an angle of between 5° and50° with respect to vertical.
 13. The system of claim 2 or claim 11 inwhich said front inclined wall is less than six inches in height. 14.The system of claim 6 or claim 11 in which a plurality of shock cordsare provided and the elastic netting is supported by the pluralityattached to the top edge of the netting and to the back court structure.15. The system of claim 2 or claim 11 wherein the top edge of theinclined wall is at a height greater than one-half the diameter of aregulation tennis ball.
 16. The system of claim 3 or claim 11 whereinthe top edge of the inclined wall is at a height equal to or slightlyless than the diameter of a regulation tennis ball.
 17. The system ofclaim 1 or claim 11 in which the screen has an upper marginal edgebinding with a projecting stop overlying the screen whereby balls movingup the screen are prevented from climbing over the top edge of thescreen.
 18. The system of claim 1 or claim 11 wherein the bottom wall ofthe trough has a groove and the screen is affixed to the trough at saidbottom edge by engaging said groove so that the trough may be readilydisconnected therefrom.
 19. The system of claim 18 wherein the bottomedge of the screen is provided with a flexible fabric of predeterminedwidth, said fabric being reinforced by rope to form a cylindrical edgethat engages said groove.